Question

Basic Electronics

6. Cathode Ray Tube (30 pts): Older television monitors used cathode ray tubes (CRT) to generate images on a screen. The CRT essentially steers an electron beam onto a phosphor coating that is located on the glass screen. By rapidly “painting" the beam across the phosphor screen, images (and hence movies) could be formed. Typically, the electron beam is deflected using magnetic fields, however, some designs also use electrostatic fields. In this problem you will analyze the electrostatic system.

The electron beam is deflected in the region 0 <= y <= d by two parallel plates with a potential difference Vo. For d <y<=d+L, there is no electric field present and the electron beam continues in a straight line based on the velocity it has at y = d.

a) Find an expression for the electric field E(y,z) between the two plates. *Hint: You can assume that the plates are infinitely large for calculation purposes.

b) Assume that at time t = 0 the electron beam starts at z(0) = y(0) = 0 with initial velocity v, (0) = v, and v,(0) = 0. Find an expression for the electron's coordinates z(t) and y(t). Assume the electron has charge q and mass m.

c) What is the vertical position, z ,of the electron when it exits the electric field region at y = d?

d) What is the velocity (v,(t) and v,(t)) of the electron when it exits the electric field region at y = d?

e) Finally, the electron beam is required to hit the phosphor screen at y = L +d, at a vertical position z = h. Find an expression for the voltage V(h) that is required such that the electron beam hits the phosphor screen at the desired height h.

Verified

### Question 44843

Basic Electronics

4a. Based on Fig. 4a, explain the fundamental working principle of a PN LED.
b. Fig. 4b shows phosphorus and boron doping of silicon. Using the diagram,explain how doping is achieved, the type of doping and the role of electrons and holes in the resultant material.
c. State the Stefan-Boltzmann law, explain its parameters and how it could be used as a basis for a passive infra-red (PIR) thermal imaging system.

### Question 44842

Basic Electronics

OExplain what is the main focus of the branch of science known as"Metrology' and how it may be related to sensors.
(b) The terms accuracy, precision, resolution and linearity are clearly defined in Metrology. Explain these terms, giving examples or-sketching diagrams to highlight key features.

### Question 44841

Basic Electronics

(a) Explain what is a low pass filter. Sketch a circuit diagram of apassive low pass filter and its bode plot for gain and phase. Explainthe significance of the -3dB point and what would the roll-off rate befor a 3rd-order low pass filter.
(b) Contrast the low pass filter with a high-pass filter. Sketch a circuit diagram of a passive high pass filter and its bode plot for gain and phase.[10 Markel
(c) What is the main difference between an active and a passive filter and contrast at least one key feature of an analogue Bessel filter versus an analogue Butterworth filter.

### Question 44840

Basic Electronics

1.(a) Many sensors have a number of key characteristics in common,such as sensitivity and stability. List a further set of 5 key characteristics and explain why they are important.
(b) Explain what type of sensor is a silicon photodiode and its operation.What are the two main configurations of a photodiode and which of these is useful if the response of the photodiode needs to be relatively fast compared to a conventional photodiode.40 Modike)

### Question 44748

Basic Electronics

The partial ac equivalent circuit of an amplifier is shown below. If R1 = 38 kohms and R2 = 1.99 kohms, find the overall voltage gain Vo/Vg (approximately)?

### Question 44747

Basic Electronics

Which of the following is the best estimate for the resistance seen by the source, Rin, and the outpu tresistance seen by the load, Ro, for the circuit shownbelow?
O 10 x R1, 1 m2
O R1, 1N
O 10 x R2, 100 ohms
R2, 4.7 kohms

### Question 44746

Basic Electronics

The amplifier shown below is very close to being an ideal trans resistance amplifier with a gain of 4.7 kohms.If Rg is 1.6 k2 and RL is 2.0 kohms, calculate the overall gain Vo/Vg.

### Question 44745

Basic Electronics

The open loop gain, Aol of an amplifier with a feedback fraction of B =0.53, changes from 100 to110 because of temperature changes (hint: a large change!). Calculate the percentage change in the closed loop gain, Af. (Don't put the % sign in the answer).Type your answer...

### Question 44744

Basic Electronics

The Transr esistance gain of an amplifier is defined as the ratio of
O The input voltage to the output current
The output current to the input voltage
O The output voltage to the input voltage
O The feedback current to the output voltage
O The output voltage to the input current

### Question 44743

Basic Electronics

Estimate the magnitude of the loop gain of the circuit shown below. The op-amp has the following parameters: differential input resistance, rd = 1 MQ,output resistance, ro = 100 ohms open-loop gain, Aol-105 assume R1= 98.30 k ohms and R2 6.90 k ohms